A color laser printer having a plurality of photosensitive drums forming electrostatic images arranged in parallel in a prescribed direction is known as an image forming apparatus.
The color laser printer includes a drum unit integrally holding a plurality of photosensitive drums. A plurality of developer cartridges are detachably mounted to the drum unit. Each developer cartridge includes a developer roller, and the developer roller feeds a toner to an electrostatic latent image formed on the corresponding photosensitive drum for developing the electrostatic latent image.
The drum unit is detachably mountable to a main body casing of the color laser printer. When the drum unit is detached from the main body casing, the developer cartridge can be detachably mounted to the drum unit.